Research Of Silver Ion Catalyzing The Pressure Leaching Of Chalcopyrite Type Copper-Gold Concentrate

With dwindling reserves of high grade and easily workable gold mineral resources,recovery of gold from deposits with complex mineralogy has emerged as an important subject which needs to be solved urgently.Its environmentally friendly and energy-saving consumption hydrometallurgical processes are in the ascendant.Therefore,the method that adding silver ion to catalyze leaching of a copper-bearing refractory gold concentrate with sulfide matrices mainly composed of chalcopyrite is proposed.The influences of parameters on the pretreatment process were evaluated and the optimal conditions for the extraction of copper from the a copper-bearing refractory gold concentrate in sulfuric acid-oxygen media adding silver ion under pressurized were determined,based on which the oxidation pretreatment process of the copper-bearing refractory gold concentrate has been improved.Parametric optimization through orthogonal experimental design was conducted for the extraction of copper from the chalcopyrite concentrate.The optimal conditions were obtained as leaching temperature 100?,leaching time 3 h,the O2 partial pressure 0.3 MPa,stirring ratio 600 r·min-1,the initial H2SO4 concentrations 100g·L-1,the liquid-solid ratio 10:1,Silver ion concentration 5 mmol·L-1,the leaching rate of copper obtained was 95.84%under the conditions-Furthermore,the experimental investigations demonstrated that two parameters,i.e.leaching temperature,and the liquid-solid ratio,were significant parameters in this leaching pretreatment system,whereas the other three were of less importance.The influences of the pretreatment process parameters,including agitation speed,initial silver ion,initial H2SO4 concentration,the O2 partial pressure,reaction temperature,the liquid-solid ratio,reaction time,were systematically investigated and discussed.The addition of silver ions increased the copper leaching rate of chalcopyrite concentrates by 43.53%.The results are of vital importance for enhancing the oxidation leaching of the chalcopyrite concentrate.Chemical analysis and XRD were used to characterize the leaching solution and the solid residues.The mechanism and the results of oxidation were identified.The effect of the structure and the component of the solid residues on the process of pre-treatment and the extraction of metals were studied,the results show the influence of the structure of the solid residues on extraction of gold and silver.The studies of the oxidation process and the leaching characteristic of chalcopyrite show that iron dissolve from chalcopyrite first,and come into be something as chalcopyrite with litter iron,further oxidized be compound of Cu and S,and oxidized lastly.The leached residues were then characterized with equipment of SEM and XRD.Results show that initial addition of silver ions remains uniformly distributed in the leaching residues.Furthermore,pyrite in the material of a copper-bearing refractory gold concentrate with sulfide matrices mainly composed of chalcopyrite is still left in the leached residues,indicating that pyrite is not oxidized and leached along with leaching of the copper-bearing refractory gold concentrate.The mechanism analysis suggests that a drop of initially added silver ion reacted with chalcopyrite to produce silver sulfide,which was mixed up with sulfur layer of product.The addition of silver destroys the denseness of sulfur on chalcopyrite surface.The experiments of extraction gold from copper-bearing gold ores by cyanidation directly and cyanidation after acid pre-treatment was done.The results show that the gold rate of extraction is low without effective pre-treatment.The effects of particle size,chemical pressure,temperature,acidity etc.on extraction of gold were investigated by the experiments of pre-treatment of the gold ores under low temperature and pressure in H2SO4-O2-Ag+system.It was acquire that the copper leaching rate of chalcopyrite concentrates by 94.80%,the extraction of gold was 98.19%,and the extraction of silver was 90.60%.It shows that the technology of oxidation pretreatment can treat copper-bearing gold ores effectively and comprehensive recovery of the useful metals.